The present invention relates to an electromagnetic fuel injection apparatus, an internal combustion engine having an electromagnetic fuel injection apparatus, and a drive circuit of an electromagnetic fuel injection apparatus. More particularly, the invention relates to an electromagnetic fuel injector comprising at least two coils for driving a valve body, and it also relates to an internal combustion engine having an electromagnetic fuel injector, and a drive circuit for an electromagnetic fuel injector.
An electromagnetic fuel injector (hereinafter simply called an injector) has a structure in which an electric signal is applied to a coil provided inside the injector, and, in response to a generated magnetic force, a plunger is moved to separate a valve body from a valve seat so that a fuel passage between the valve body and the valve seat is opened to allow fuel to be injected from a fuel injection orifice.
In the above-stated injector, as a means for forcing the valve body toward the valve seat in the closing direction, a return spring ember is provided, so that when application of the electric signal to the oil is stopped, the magnetic attraction force which moves the plunger in the opening direction is attenuated, and the fuel passage between the valve body and the valve seat is closed, namely the injector is closed.
In Japanese application patent laid-open publication No. Hei 8-326620, an electromagnetic fuel injector is disclosed, in which two coils are provided. At an initial stage of a valve opening operation, where a closed valve state is shifted to a valve opening operation application of electric signals to the two coils is performed; which, after the valve has opened, only one coil is energized to hold the valve open. In this conventional injector, each of the above-stated two coils is formed to have the same size and the same configuration. In this conventional injector, by the application of electrical signals to the two coils during the valve opening operation, the magnetic attraction force is made large and the valve opening delay can be shortened; and, during the time the valve is being held open, the magnetic attraction force is small, and so the valve closing delay time can be shortened.
In the conventional injector disclosed in Japanese application patent laid-open publication No. Hei 8-326620, as stated above, no consideration is given to the possibility that advantages can be achieved of the electric characteristic of the two coils is designated to be different from one another. For this reason, there are problems in that, when an attempt is made to assure a high speed response performance during valve opening, it is difficult to obtain a magnetomotive force necessary to maintain the valve in the open condition; on the other hand, when an attempt is made to assure a stable performance during the time the valve is held open, it is difficult to obtain a high speed response performance.
Accordingly, in the above-stated conventional injector, it is not easy to design a structure in which the high speed response performance is compatible with the stability performance during the tine the valve is being held open for fuel injection.
An object of the present invention is to provide an electromagnetic fuel injection apparatus, an internal combustion engine having an electromagnetic fuel injection apparatus, and a drive circuit of an electromagnetic fuel injection apparatus, wherein a drive force of a desirable characteristic for control of a valve body of the electromagnetic fuel injection apparatus can be generated to effect operation of the electromagnetic fuel injection apparatus.
To attain the above-stated object, an electromagnetic fuel injection apparatus, comprising an electromagnetic fuel injector and a drive circuit for driving the electromagnetic fuel injector is provided, wherein the electromagnetic fuel injector has at least two coils having a different time change rate of magnetomotive force, and to the at least two coils, a different voltage is applied.
Further, to attain the above stated object, an electromagnetic fuel injection apparatus, comprising an electromagnetic fuel injector and a drive circuit for driving the electromagnetic fuel injector, is provided, wherein the electromagnetic fuel injector has at least two coils having a different winding number, and to the at least two coils, a different voltage is applied.
Further, to attain the above-stated object, an electromagnetic fuel injection apparatus, comprising an electromagnetic fuel injector and a drive circuit for driving the electromagnetic fuel injector, is provided, wherein the electromagnetic fuel injector has at least two coils having a different length, and to the at least two coils, a different voltage is applied.
Further, to attain the above-stated object, an electromagnetic fuel injection apparatus, comprising an electromagnetic fuel injector and a drive circuit for driving the electromagnetic fuel injector, is provided, wherein the electromagnetic fuel injector has at least coils having a different cross-sectional area of wire material, and to the at least two coils, a different voltage is applied.
Further to attain the above-stated object, an electromagnetic fuel injection apparatus, comprising an electromagnetic fuel injector and a drive circuit for driving the electromagnetic fuel injector, is provided, wherein the electromagnetic fuel injector at least two coils having a different electric resistance value between the terminals thereof, and to the at least two coils, a different voltage is applied.
In the above-stated electromagnetic fuel injection apparatus, to one of the at least two coils, which has a large time change rate of magnetomotive force, a high voltage is applied, and to another of the at least two coils, which has a small time change rate of magnetomotive force, a low voltage is applied.
Further, to attain the above-stated object, an electromagnetic fuel injection apparatus, comprising an electromagnetic fuel injector and a drive circuit for driving the electromagnetic fuel injector, is provided, wherein the fuel injector has a fuel injection orifice, a seat valve provided upstream of the fuel injection orifice, a valve body for performing an opening and closing of a fuel passage between the valve seat and the valve body, and at least two coils for generating a drive force of the valve body. In the electromagnetic fuel injector, there is provided a first coil having a large time change rate of magnetomotive force, which is a product of the winding number and a current value, and a second coil having a smaller time change rate of magnetomotive than that of the first coil, and a switching means is connected to the first coil for performing an on and an off application of a first voltage, and a second switching means is connected to the second coil, for performing an on and off application of a second voltage lower, than the first voltage.
Further, to attain the above-stated object, an electromagnetic fuel injection apparatus, comprising an electromagnetic fuel injector, a drive circuit for driving the electromagnetic fuel injector and a control circuit for sending a control signal to the drive circuit, is provided wherein the electromagnetic fuel injector has a fuel injection orifice, a seat valve provided upstream of the fuel injection orifice, a valve body for performing an opening and closing of a fuel passage between the valve seat and the valve body, and at least two coils for generating a drive force to effect movement of the valve body wherein a first coil has a large time change rate of magnetomotive force, which is a product of the winding number and a current value, and a second coil has a smaller time change rate of magnetomotive than that of the first coil. In the drive circuit, for controlling the first coil, a switching means is provided for performing an on and off application of a first voltage, and for controlling the second coil, a second switching means is provided for performing an on and off application of a second voltage lower than the first voltage. In the control circuit, at an initial stage of the valve opening operation of the valve body, a first voltage is sent to the first coil and a second voltage is sent to the second coil to generate a magnetic flux having the same direction, and, after that, only the second voltage is sent to the second coil.
In the above-stated electromagnetic fuel injection apparatus, a circuit means for regulating the second voltage is provided.
in the above-stated electromagnetic fuel injection apparatus, the drive circuit is installed inside of an engine control unit which controls an operation condition of an internal combustion engine.
Further, to attain the above-stated object, an internal combustion engine has an electromagnetic fuel injection apparatus according to the present invention for injecting fuel, a fuel supply means for supplying the fuel to the fuel injection apparatus, a plurality of cylinders in which the fuel injected by the fuel injection apparatus is burned, an air intake means for supplying air to the cylinders, an ignition means for igniting an air-fuel mixture in each cylinder, an air exhaust means for exhausting gas from each cylinder, and an engine control unit for controlling the air intake means, the air exhaust means, the ignition means and the fuel injection apparatus. The electromagnetic fuel injection apparatus comprises an electromagnetic fuel injector and a drive circuit for driving the electromagnetic fuel injector, and the electromagnetic fuel injector has a fuel injection orifice, a seat valve provided upstream of the fuel injection orifice, a valve body for performing an opening and closing of a fuel passage between the valve seat and the valve body, and at least two coils for generating a drive force to effect movement of the valve body, including a first coil having a large time change rate of magnetomotive force, which is a product of the winding number and a current value, and a second coil having a smaller time change rate of magnetomotive than that of the first coil. In the drive circuit, to control the first coil, a switching means is provided for performing an on and off application of a first voltage, and to control the second coil, a second switching means is provided for performing an on and off application of a second voltage lower than the first voltage.
Further, to attain the above-stated object, an internal combustion engine has an electromagnetic fuel injection apparatus according to the present invention for injecting fuel, a fuel supply means for supplying the fuel to the fuel injection apparatus, a plurality of cylinders in which the fuel injected by the fuel injection apparatus is burned, an air intake means for supplying air to the cylinders, an ignition means for igniting an air-fuel mixture in each cylinder, an air exhaust means for exhausting gas from each cylinder, and an engine control unit for controlling the air intake means, the air exhaust means, the ignition means and the fuel injection apparatus. The electromagnetic fuel injection apparatus includes an electromagnetic fuel injector and a drive circuit for driving the electromagnetic fuel injector, and the electromagnetic fuel injector has a fuel injection orifice, a seat valve provided upstream of the fuel injection orifice, a valve body for performing an opening and closing of a fuel passage between the valve seat and the valve body, and at least two coils for generating a drive force to effect movement of the valve body, including a first coil having a large time change rate of magnetomotive force, which is a product of the winding number and a current value, and a second coil having a smaller time change rate of magnetomotive than that of the first coil. There is provided a first power supply for supplying a first voltage to the first coil and a second power supply for supplying a second voltage to the second coil, the first voltage being a high voltage supplied to the first coil and the second voltage being a lower voltage than the first voltage of the first power supply and being supplied to the second coil to stabilize the operation of the fuel injection apparatus.
Further, to attain the above-stated object, in an electromagnetic fuel injection apparatus comprising a valve seat, a valve body for performing an opening and a closing of a fuel passage between said valve seat and the valve body, a coil, and a drive means for driving said valve body to effect opening and closing of said fuel passage to control fuel injection, the drive circuit of the electromagnetic fuel injection apparatus has a reverse flow prevention diode for preventing reverse current flow in a coil at the time of application of a voltage as a result of a mutual inductance.